Hair have a protecting role and are considered as a skin annex along with sebaceous glands, sudoriferous glands and nails. Hair have a unique and peculiar feature: cyclicity.
The life cycle of the hair bulb is essentially represented by three subsequent phases: anagen (growth), catagen (involution) and telogen (rest phase).
The period of hair growth is followed by a regression phase, during which the deepest part of the follicle undergoes programmed cell death.
At the end of this phase, the cycle restarts. The biological phases of this phenomenon reside in the capability of stem cells of the bulb to leave, at alternating steps, their state of quiescence. During the bulb growth and hair production phase the proliferation, differentiation and survival activities are prevailing which are regulated by growth factors. The regression phase, on the contrary, is characterized by the activation of molecular pathways that induce apoptosis in bulb cells.
If the role of hair is considered in social relations, hair loss may be hard to face for many people.
In the anagen phase, the dermal papilla generates chemical signals that activate and instruct the stem cells of the bulge which by migrating to the base of the follicle form the hair matrix. With this “migration” the stem cells of the bulge create a “path” of cells which will give rise to the outer root sheath or ORS.
In response to further signals by the dermal papilla, the matrix cells, which derive from stem cells, proliferate and start the differentiation process, by moving upwards to form the shaft and inner sheath of the hair follicle.
The start of catagen is characterized by the end of cell proliferation and the apoptosis of matrix cells. During catagen the dermal papilla migrates towards the lowermost portion of the bulge. This close proximity of the papilla to the bulge is believed to be essential for initiating another hair production cycle. This enables interaction/activation of bulge cells at rest and a new cycle of hair growth.
Upon catagen/telogen transition, some cells of the bulge migrate to meet the papilla, generating the hair germ.
Hair in telogen contains a cell population at its base, which is in fact called hair germ, located in close proximity to the dermal papilla. The hair germ is activated to proliferate towards the end of the telogen phase, even before the bulge, to form, by surrounding the papilla, the matrix of the new bulb.
Different factors, among which stress, the lack of nutrients and ageing, negatively affect the life cycle of the hair bulb, determining a reduction of the number of hair and their thinning.
In individuals suffering from androgenetic alopecia (AGA), over time the follicles, which are formed again at the beginning of the new anagen phase, become smaller in size, leading to the formation of hair with smaller diameter as compared to the initial diameter. As a consequence, the formation of microscopic hair occurs. It was observed that although the follicles of scalp atrophy, there still remains a supply of stem cells which convert to progenitor cells, even though to a lesser extent as compared to the scalp in physiological conditions.
Most of the hair preparations available on the market target hair bulbs and act on scalp metabolism, feeding, oxygenation and microcirculation improving the conditions contributing to a physiological growth of hair.
Different products and treatments are available on the market to treat and prevent hair loss. However, the use of those products that to date have shown to be particularly effective in treating hair loss, such as minoxidil or some anti-steroidal drugs of a synthetic origin, is not free from drawbacks. Specifically, the topical use of minoxidil may determine the occurrence of side effects of a certain degree such as skin rashes, local inflammations, cephalea, while the oral administration of drugs such as finasteride may determine the appearance of hormonal dysfunctions with potential negative effects on sex life.
Other products currently used in the trichological field, in spite of being based on products of a natural origin, on the contrary, have the drawback of being made through complex preparation processes and, therefore, are particularly expensive. Consequently, there is currently a need to provide products containing substances that are active in stimulating the physiological process of hair growth and the use of which does not cause significant side effects.
One of the objects of the invention is to provide a composition or preparation containing active agents of a non-synthetic origin which are suitable for stimulating the physiological hair growth in subjects suffering from hair loss or thinning and the use of which is nearly free from significant side effects.
Another object of the invention is to provide a composition for trichological use which may be applied locally or administered orally, the active agents of which are of a vegetal origin obtainable via simple methods.